It does have a more pronounced tendency to warp than the ABS I have used so far.On the plus side it does have a very nice & smooth surface - as far as I can say that with my bugy N2.

After printing a 20x20x10mm test cube (100% infill), I found that this box is 1,75% bigger in X- and Y-directionthan it should be (20,35mm instead of 20,00 mm).So I want to compensate for that before I print things to be really used.(Yes, I am an optimist and believe that I can really print useful things with my doomed N2 somewhen in time...).

The only possibility to compensate in X- and Y-direction in relation to the material usedis under "advanced/Other/XY Size Compensation.But there one can only enter an absolute dimensional value, e.g. 0,35mm.This would be okay for my test cube - but what I really need is an relative value (e.g. 1,75%), right?Since I do not want to just print test cubes;-)

Achieving dimensional accuracy isn’t as simple as a single scale measurement. I use S3D for slicing and it has X, Y, Z part scaling plus a horizontal offset. I don’t know IdeaMaker well, but I’m guessing X and Y-axis compensations in the Printer Settings dialog work for XY scale. Part Scaling can also work, although I don’t know why they have chosen Width Depth and Height over X, Y, and Z. Under the OTHER tab, XY size compensation may be the same as S3D’s Horizontal Offset.

Attached you will find a part I'm calling a Calibration Cross - STL and JPG drawing. It includes internal and external features, both large and small. I have also attached an Excel Spreadsheet (Zipped) which allows you (by trial and error) to see the impact of scaling and horizontal offset values in correcting part dimensions.

Print off a Calibration Cross with no scaling and no horizontal offset. Enter the measured values into the spreadsheet and experiment with different X & Y scale factors as well as the horizontal offset value to minimize the resulting error on all of the measured dimensions. The solver add-in can help narrow in on the best values.

Whenever I’m going to print using a new setup, filament, significantly different print speed, layer height, temperature, etc, I start by running a Calibration Cross and use the spreadsheet to calculate scaling and offset numbers. This technique has proven to be a reliable way to ensure dimensional accuracy on parts. The Z-scale on my N2+ has proven to be quite accurate, so I just use 100% on that.

I can generally achieve part accuracy better than +/- .1mm (.004") on all dimensions.

I meant to include this, even though it doesn't seem needed for the N2 machine - but here's my part for checking Z scale. I think there are fields for this in the version of the spreadsheet I attached.

Tinkerer, I think you are mixing up things here.I assume that you have used a heated bead when printing ABS, probably at 110 °C, as is normally used.Due to the thermal expansion of ABS, your model will therefore always end up be smaller than expected, when it is cooled down and removed from the build plate.I always SCALE UP my ABS models in X and X direction by 100.7 % when slicing the model. I think that corresponds to zemlins results.

The fact that you measure 20.35 mm on a 20 mm cube could be caused by severe over-extrusion (or a measurement error). Otherwise your cube would be smaller than the nominal 20 mm, i.e. approx. 19.86 mm.

The X/Y Compensation in Printer Settings is for your printer. It should be a fixed value for one printer for hardware compensation.If for one filament, should edit flowrate in Filament Settings to adjust the extrusion amount.The X/Y Size Compensation in Advanced Settings is for outer shells of the model, especially for size of hole structure.

For flowrate adjusting, I will recommend more to do a flowrate calibration first.

I have argued before, that it is a misconception from Raise3D to put X/Y compensation in printer settings.The relationship between X/Y travel and the number of step-pulses is fixed, in the sense that one full-step is exactly 0.2 mm and one 1/16 micro-step is exactly 12.5 µm. The only parameter that has an influence on this relationship is the mean tooth distance of the belts. There are no other mechanical parameters/tolerances in the printer that affect this relationship. The glass-fiber enforced GT2 belts used in the printer are extremely precise when it comes to mean tooth pitch, even over temperature, and I never heard of anybody who found it necessary or possible to calibrate a GT2 belt.A much larger dimensional variation comes from material shrinking with temperature, for example when printing ABS with heated bead and a warm enclosure. Therefore, the only rational use of x/y compensation is for material shrinking compensation, and therefore these settings ought to be moved out of the printer settings menu of ideaMaker.This is like other slicers do. Simplify3D has X/Y/Z compensation for the indiviual models that you have added to your print, -not for the printer!

When you are only concerned about the outer dimensions of a model, like Tinkerers 20 mm cube, then the "X/Y compensation" feature can be used perfectly well for material contraction compensation.It is more tricky, when a model also needs to preserve internal dimensions. If the model has holes for example, then the hole dimension will increase when the material cools and contracts and the X/Y compensation will need to be negative to preserve a hole dimension. For example you would want to use an X/Y compensation of 99.3% to get correct hole sizes when printing with ABS @110 degC heatbed temperature.In Simplify3D there is another feature called "Horizontal Size Compensation". This feature can expand or retract the model in a similar way as material contraction/expansion. However, for some strange reason this compensation is given in "mm" and not "%" and that makes it a little tricky to use. If you have a model with an outer dimension of for example 100 mm and with 3 mm diameter holes, you would want to set "Horizontal Size Compensation" to 0.7 mm to preserve the outer dimension of 100.0 mm. This however means that your 3 mm holes will end up having a diameter of approx. 3 mm - 2*0.7 mm = 1.6 mm, which is obviously not acceptable. So, in Simplify3D I tend to switch between the absolute "Horizontal Size Compensation" and the relative "X/Y compensation", depending on the shape of the model and which dimensions are important to preserve. The ideal tool would be "Horizontal Size Compensation" as a relative compensation (%).

Last edited by ABH on Sat Dec 09, 2017 5:28 pm, edited 1 time in total.

ABH wrote:for some strange reason this compensation is given in "mm" and not "%" and that makes it a little tricky to use.

In S3D I find the horizontal compensation as mm to make perfect sense. I use it in combination with the scaling factors. Using the tools I posted above I get very accurate and reliable dimensions by running a single test print.

ABH wrote:zemlin, if you can accept that nominal Ø3mm holes becomes Ø4.4 mm, as described in my example above, then I agree, that this feature can be used. If not, then you have to use X/Y compensation instead.

You clearly don't understand my methodology. I am a machine design engineer and machinist. I understand precision and I make parts that work. In general my maximum tolerance on large or small, inside or outside features is less than .1mm.

No, sorry Zemlin, I didn't understand your system at first, because I didn't know that by "Offset Compensation" in Simplify3D you were in fact referring to "Horizontal Size Compensation", but that is clear now. I agree that this compensation can be thought of as an offset on all dimensions; negative offset on inside dimensions and positive offset on outside dimensions.So, basically in Simplify3D you can adjust "scaling" (called "X/Y compensation") and "offset" (called "Horizontal Size Compensation").In ideaMaker you only have "scaling" (x-axis and y-axis compensation). As to my knowledge, there is no "offset" in ideaMaker, so your system only works with Simplify3D.

Your idea of using an empirical method for finding a good combination of offset and scaling is probably good. At least you can minimize the error for the calibration cross, but will your settings also be optimal for other model shapes?